Optically brightened compositions with unsymmetrical carboxystyrylphenyl-containing compounds

ABSTRACT

BENZOFURANS, BENZOTHIOPHENES, AND NAPTHOFURANS WHICH ARE SUBSTITUTED BY CARBOXYSTYRYLPHENYL GROUPS ARE OPTICAL BRIGHTENING AGENTS USEFUL FOR WHITENING AND BRIGHTENING NATURAL AND SYNTHETIC FIBERS, PAPERS, RESINS AND THE LIKE. THE COMPOUNDS ARE CONVENIENTLY PREPARED BY INTERACTING BENZOFURANS, BENZOTHIOPHENES OR NAPTHOFURNAS, WHICH ARE SUSBTITUTED BY A P-TOLYL GROUP, WITH AN AROMATIC ALDEHYDE OR PREFERABLY THE ANIL DERIVATIVE THEREOF.

United States Patent (Office 3,833,510 Patented Sept. 3, 1974 U.S. Cl. 252-3012 W 4 Claims ABSTRACT OF THE DISCLOSURE Benzofurans, benzothiophenes, and naphthofurans which are substituted by carb'oxystyrylphenyl groups are optical brightening agents useful for whitening and brightening natural and synthetic fibers, papers, resins and the like. The compounds are conveniently prepared by interacting benzofurans, benzothiophenes or naphthofurans, which are substituted by a p-tolyl group, with an aromatic aldehyde or preferably the anil derivative thereof.

This invention relates to compositions of matter classified in the art of chemistry as substituted benzofurans, benzothiophenes and naphthofurans, to processes for their preparation, and to polymeric compositions containing them.

The compounds of this invention are useful as fluorescent whitening and brightening agents for treatment of threads, sheets, films, filaments, textile fabrics, castings, moldings, and the like as well as in the manufacture of textiles, paper, varnishes, inks, coatings and plastics. These compounds are particularly valuable because of their strong blue shade of fluorescence and their excellent stability to light, chlorine-type bleaches and elevated temperatures.

In its composition of matter aspect, the invention sought to be patented resides in the novel chemical compounds of Formula I COOR Q-Q-CILAJH-Q Formula I wherein: Q is a monovalent aromatic heterocyclic radical selected from the class having the formulas X is oxygen or sulfur; Z is naphtho (that is, 1,2-naphtho, 2,1-naphtho or 2,3-naphtho); R is hydrogen, lower-alkyl having one to three carbon atoms or hydroxy-lower alkyl having two or three carbon atoms; R and R are the same or different and are members of the class consisting of hydrogen, alkyl having one to six carbon atoms, alkoxy having one to six carbon atoms, and halo; R and R are the same or different and are members of the class consisting of hydrogen, alkyl having one to six carbon atoms, al'koxy having one to six carbon atoms, cyano, halo, dialkylamino wherein each alkyl has one to six carbon atoms, alkanoylamino having one to six carbon atoms, phenyl, phenyl substituted by alkyl having one to six carbon atoms, halo, alkoxy having one to six carbon atoms, and alkanoylamino having one to six carbon atoms.

In its process aspect, the invention sought to be patented resides in the method which comprises interacting a compound of the formula Q-QCH:

Formula II with an aldehyde of the formula COOH or the anil thereof to produce a compound of Formula I in which R is hydrogen, and if desired, esterifying this compound or appropriate carboxylic functional derivative' thereof with a compound of the formula R-OH wherein R is lower alkyl having one to three carbon atoms or hydroxy-lower alkyl having two or three carbon atoms; and Q, R R R R X, and Z each have the same significance as in Formula I, to yield a stilbene compound of Formula I in which R is lower-alkyl having one to three carbon atoms or hydroxy-lower alkyl having two to three carbon atoms.

When R is in the formulas herein is lower alkyl having one to three carbon atoms, there are included methyl, ethyl, propyl, and isopropyl.

When R in the formulas herein is hydroxy-lower alkyl having two or three carbon atoms, there are included CH CH CH OH, --CH CH(OH) CH and -CH(OH)CH CH When R R R and R in the formulas herein are halo, there are included chloro, fluoro, bromo, and iodo. The preferred halo substituent is chloro because the other halogens olfer no particular advantages over chloro and because of the relatively low cost and ease of preparation of the required chloro intermediates. However, the other above-named halo substituents are also satisfactory.

When R R R and R in the formulas herein are alkyl having one to six carbon atoms, there are included, for example, methyl, ethyl, propyl, isopropyl, butyl, sec.- butyl, tert.-butyl, isobutyl, amyl, hexyl, 2,3-dimethy1butyl, and the like.

When R R R and R in the formulas herein are alkoxy having one to six carbon atoms, there are included, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert.-butoxy, amyloxy, hexyloxy, and the like.

When R and R in the formulas herein are dialkylamino, each alkyl group having from one to six carbon atoms, there are included for example, dimethylamino, diethylamino, dipropylamino, dibutylamino, dipentylamino, dihexylamino, methylethylamino, N methyl N-butylamino, and the like. For the purposes of this invention the common amino radicals wherein the two alkyl groups are joined to form a ring, for example, pyrrolidino, piperidino, morpholino, thiomorpholino, and N-methylpiperazino, are equivalent to the dialkylamino compounds claimed herein.

When R and R in the formulas herein are alkanoylamino having one to six carbon atoms, there are included, for example, formamido, acetamido, propionamido, butyramido, isobutyramido, valeramido, isovaleramido, caproamido, and the like.

When R and R in the formulas herein are substituted phenyl, there are included, for example, p-tolyl, o-tolyl, m-tolyl, p-ethylphenyl, p-acetamidophenyl, o-acetamidophenyl, m-hexanoylaminophenyl, p-chlorophenyl -chloro phenyl, m-bromophenyl, o-methoxyphenyl, p-ethoxyphenyl, 2,4-dimethoxyphenyl, 3,4-dichlorophenyl, 2,4-dimethylphenyl, and the like.

In general, the compounds of Formula I are highmelting yellow solids. They are insoluble in Water, the lower alcohols, ketones and mineral acids and moderately soluble in dimethylformamide and high-boiling, non-polar aromatic hydrocarbons. The alkali metal or ammonium salts of the carboxylic acid substituted compounds have low solubility in water and are generally moderately soluble in Z-ethoxyethanol and dimethylformamide.

When the compounds of the present invention are dispersed or dissolved in aqueous media, they fiuoresce bluewhite under ultraviolet light. They are particularly substantive to a wide variety of natural and synthetic fibers, for example cotton, cellulose acetate, viscose rayon and nylon, and are absorbed by such fibers from very low concentrations in aqueous dispersions. Furthermore the compounds of this invention are particularly adapted to incorporation into plastic and synthetic fiber melts and to application to fabrics by the known heat-setting procedures. These compounds also have high stability to sunlight, soap, synthetic detergents and chlorine-type bleaches.

The above-described properties of the compounds of Formula I make them especially valuable as fluorescent whitening and brightening agents in treating white. and colored fabrics in order to neutralize the yellowness which develops with age in white textiles and to enhance the brilliance of colored textiles. In such utilization the high resistance of these compounds to chlorine bleaches and to light are distinct advantages. Another valuable advantage offered by these compounds is their unusual stability at high temperatures, which permits their use in high melting polymers. A further important advantage of the compounds of this invention lies in their property of building up the amount of the whitening agent without developing an undesirable discoloration, for example a reddish or grey color, such as is produced by many of the known optical bleaching agents when they are applied repeatedly, as in successive launderings.

The manner and process of making and using the invention, and the best mode contemplated by the inventor of carrying out the invention, will now be described so as to enable any person skilled in the art to which it pertains to make and use the same.

In general, the compounds of this invention wherein R in Formula I is hydrogen are conveniently obtained by interacting an appropriate carboxylic acid-substituted benzaldehyde (for example, a phthalaldehydic acid, an isophthalaldehydic acid or a terephthalaldehydic acid) or preferably the anil derivative of such aromatic carboxaldehyde, with a compound having the structure Formula III for obtaining those final products in which Q is a benzofuran or benzothiophene moiety and with a compound having the structure.

i --CH: 0

Formula IV for obtaining those final products in which Q is a naphtho: furan moiety. The symbols R R R X and Z each have the same respective meanings as herebefore given With respect to Formula I. This reaction can be usually be carried out at moderate temperatures, for instance in the range 0-55 C., in a suitable solvent and in the presence of a strongly alkaline reagent. Under these conditions, the reaction is generally complete in approximately one-half to three hours.

Suitable solvents are those highly polar solvents which are free of acidic hydrogen or other atoms or radicals which may react with strongly alkaline reagents. Examples of suitable solvents include dimethylformamide, dimethylacetamide, diethylformamide, hexamethylphosphoramide, N-formylpiperidine, and sulfolane.

The strongly alkaline reagents suitable for the condensation include the alkali metal salts of tertiary aliphatic alcohols, alkali metal hydroxides, alkali metal amides and alkali metal hydrides. However, the nature of the alkaline reagent (other than its basicity) is not critical to the invention, and any alkaline compound of comparable basicity under the reaction conditions can be employed herein.

Because of the reactive nature of the alkaline reagent, it is preferable to conduct this condensation reaction in a manner which will exclude atmospheric moisture and carbon dioxide. Accordingly, for such purpose an atmosphere of dry nitrogen or other inert gas over the reaction medium is provided.

The compounds of Formula I in which R is other than hydrogen, that is, lower alkyl or'hydroxy-lower alkyl, are readily prepared by esterifying a free carboxylic acid compound of Formula I with the appropriate lower alkanol or lower alkanediol. The esterification of the free carboxylic acid substituted compounds of Formula I (wherein R is hydrogen) to obtain the corresponding compounds of the same formula in which R is lower alkyl or hydroxy-lower alkyl is accomplished by utilizing any one of several art-known methods for preparing carboxylic esters from appropriate carboxylic functional derivatives, for example, free carboxylic acids, carboxylic acid halides or other esters. However, it is particularly convenient for the purposes of this invention to utilize the free carboxylic acid compounds of Formula I in the wellknown two-step method which comprises first converting the carboxylic acid to the corresponding acid chloride and then interacting the acid chloride with the desired lower alkanol or lower alkanediol.

The requisite 2-(p-tolyl)-substituted intermediates of Formulas III and IV are generally known compounds prepared according to procedures well known to those skilled in the art, for instance by cyclizing an appropriate phenyl or naphthyl 4-methylphenacyl ether or thioether.

The final products of this invention can be obtained by the interaction of the p-tolyl-substituted compounds of Formula III and Formula IV, with the appropriate carboxylic acid-substituted benzaldehyde. However, it is preferred to use the anil derivative of the aromatic carboxaldehyde because of the substantially higher degree of reactivity of these derivatives than that of the aldehyde with the p-tolyl-substituted starting materials. The requisite anil derivatives and methods for their preparation, for example, by the interaction of aniline with the aromatic carboxaldehyde, are well known and have been described in the prior art. Although the anil derivatives employed in this invention were prepared from unsubstituted aniline, it will be obvious that anilines bearing substituents on the ring, which are inert under the conditions of the processes of this invention, for example, lower-alkyl, lower-alkoxy, halogen, etc. can also be employed, if desired.

The derivatives obtained by the reaction of aniline with each of the three carboxylic acid-substituted benzaldehydes, that is, phthalaldehyde acid, isophthalaldehydic acid, and terephthalaldehydic acid, have been described in the literature. The aniline derivatives of isophthalaldehydic acid and of terephthalaldehydic acid are described as existing in the imine (Schifls base) form (anils). On the other hand, the aniline derivative of phthalaldehydic acid is described as being the cyclic compound, 3-anilinophthalide. This intermediate is as fully reactive and useful in the processes of this invention for obtaining the 2- carboxystyryl-substituted compound as are the anils of the isophthalaldehydic and terephthalaldehydic acids for obtaining the 3-carboxystyry1- and the 4-carboxystyrylsubstituted compounds, respectively. Accordingly, as used throughout this application, the term anil is intended to include the cyclic 3-anilinophthalides obtained from the phthalaldehydic acids as well as the imine forms obtained from the isophthalaldehydic and the terephthalaldehydic acids.

A preferred mode of utilizing the compounds of Formula I is to incorporate them into melts of synthetic polyester plastic material for spinning synthetic fibers or for casting or molding plastics in an appropriate concentration, for example 0.01 to 0.1 percent by weight of the melt wherein the polyester materials are selected from the class consisting of poly(ethylene terephthalate) and poly- (1,4-cyclohexylenedimethylene terephthalate) A further method of utilizing the compounds of Formula I is to impregnate textile fabrics comprising synthetic fibers, for example polyester (poly[terephthalic acid ethylene glycol ester]) or nylon, with an aqueous dispersion of the compound at temperatures below about 75 C., for example, at room temperature and then to subject the treated fabric to a dry heat treatment at a temperature above 100' C. The fabric may advantageously be dried at temperatures in the range 60l00 C. prior to the heat treatment, which is preferably carried out at temperatures in the range 125-250 C. Said heat treatment may be accomplished by any of several known methods, for example, by heating in a drying chamber, by ironing the fabric, or by treating it with dry superheated steam.

The structures of the compounds of this invention were established by the modes of synthesis, by elementary analysis, and by ultraviolet, infrared, and nuclear magnetic resonance spectra. The course of the reactions was followed and the homogeneity of the products thus obtained was ascertained by use of thin layer chromatography.

The invention is illustrated by the following example without, however, being limited thereto. Melting points are uncorrected except where otherwise indicated.

EXAMPLE 1 A stirred solution of 2.24 g. (0.01 mole) of 2-(p-tolyl) benzothiophene and 2.25 g. (0.01 mole) of the anil derivative of terephthalaldehydic acid in 150 ml. of freshly distilled, dry dimethylformamide was flushed with nitrogen for ten minutes. The solution was heated to 35 C. and 6.72 g. (0.06 mole) of potassium tert-but-oxide was added. The color of the reaction mixture changed from violet to brown. Analysis of an aliquot by ultraviolet spectroscopy showed that the reaction was completed after two hours of stirring. Glacial acetic acid was added in amount sufiicient to neutralize excess potassium tert-butoxide, and the reaction mixture was heated to reflux and filtered while hot to collect the resulting precipitate. The filter cake was washed with hot dimethylformamide containing two percent aniline, then slurried in hot ten percent aqueous hydrochloric acid and refiltered. The collected precipitate was washed on the filter with water until free of acid and then dried in vacuo. The product was finally purified by sublimation to obtain 2-[4-(4-carboxystyryDphenyl]benzothiophene which remained unmelted at 350 C. The wavelength of maximum excitation of this compound was 367 nm. and the wavelength of maximum emission was 423 nm.

EXAMPLE 2 Proceeding in a manner similar to that described in Example 1 above, 2-(p-tolyl)benzofuran (2.08 g.; 0.01

6 mole) was interacted with 2.25 g. (0.01 mole) of the anil derivative of terephthalaldehydic acid in the presence of 6.72 g. (0.06 mole) of potassium tert-butoxide in 150 ml. of dimethylformamide. The resulting product was purified by sublimation to obtain 2-[4-(4-carboxystyryl) phenyl]benzofuran which melted at 348349 C. The wavelength of maximum excitation of this compound was 365 nm. and the wavelength of maximum emission was 425 nm.

EXAMPLE 3 Following the procedure outlined in Example 1 above, 5-phenyl-2-(p-tolyl)benzofuran was interacted with an equimolar quantity of the anil derivative of terephthalaldehydic acid to give 5-phenyl-2-[4-(4-carboxystyryl) phenyl]benzofuran. After purification by sublimation, the product remained unmelted at 350 C. The wavelength of maximum excitation of this compound was 371 nm. and the wavelength of maximum emission was 432 nm.

EXAMPLE 4 Proceeding in a manner similar to that in Example 1 above, 5-methoxy-2- (p-tolyl)benzofuran was reacted with an equimolar quantity of the anil derivative of terephthalaldehydic acid to produce 5-methoxy-2-[4-(4-carboxystyryl)phenyl]benzofuran, which when purified by sub limation, remained unmelted at 350 C. The wavelength of maximum excitation of this compound was 376 nm., and the wavelength of maximum emission was 440 nm.

EXAMPLE 5 When S-chloro-Z-(p-tolyl)benzofuran was condensed with the anil derivative of terephthalaldehydic acid according to the procedure described in Example 1, there was obtained 5-chloro-2-[4-(4-carboxystyryl)phenyl]benzofuran which melted at 347348 C. following recrystallization from trichlorobenzene. The wavelength of maximum excitation of this compound was 372 nm. and the wavelength of maximum emission was 424 nm.

EXAMPLE 6 Seven and one-half grams (0.02 mole) of 5-chloro-2 [4-(4-carboxystyryl)phenyl]benzofuran prepared in accordance with the procedure described in Example 5 above, was reacted with thionyl chloride in 400 ml. of chlorobenzene at C. The excess thionyl chloride and chlorobenzene were distilled off. To the acid chloride remaining in the flask, there was added 200 g. (6.25 mole) of methyl alcohol in the presence of 4.0 ml. of pyridine. The reaction mixture was refluxed for sixteen hours, and then allowed to cool. The resulting product was collected on a filter and was purified by recrystallization from dichlorobenzene and cyclohexanone. The 5-chloro-2-[4-(4- carbomethoxystyryl)phenyl]benzofuran thus obtained melted at 265-267 C. The wavelength of maximum excitation of this compound was 372 nm. and the wavelength of maximum emission was 436 nm.

EXAMPLE 7 Proceeding in a manner similar to that in Example 6 above, S-chloro 2 [4-(4-carboxystyryl)phenyl]benzofuran was interacted with thionyl chloride and the acid chloride was then interacted with ethylene glycol in the presence of pyridine. The product, when recrystallized from dichlorobenzene, gave pure 5-chloro-2-{4-[4-carbo- (Z-hydroxyethoxy)styryl]phenyl}benzofuran which melted at 239243 C. This compound showed maximum excitation wavelength at 373 nm. and showed maximum emission wavelength at 439 nm.

EXAMPLE 8 Following the procedure outlined in Example 5 above, except that 3-anilinophthalide was used in place of the anil derivative of terephthalaldehydic acid, there was obtained 5-chloro 2 [4-(Z-carboxystyryl)phenyl]benzofuran. The product was subjected to purification by reprecipitation of the free acid with hydrogen chloride gas from a solution of the sodium salt in ethanol. The dried, reprecipitated product melted at 290-295" C., and showed the wavelength of maximum excitation at 362 nm. and the wavelength of maximum emission at 417 nm.

EXAMPLE 9 Following the procedure outlined in Example 8 above, 2-(p-tolyl)naphtho[2,1-b]furan was interacted with an equimolar amount of 3-anilinophthalide. After recrystallization from chlorobenzene, the thus obtained 2[4-(2- carboxystyryl)phenyl]naphtho[2,1 b]furan melted at 233-235 C. The wavelength of maximum excitation of this compound was 377 nm. and the wavelength of maximum emission was 448 nm.

EXAMPLE 10 Following the procedure as in Example 8, Z-(p-tolyl) naphtho[l,2-b]furan was interacted with an equimolar quantity of 3-anilinophthalide to produce 2-[4-(2-carboxystyryl)phenyl]naphtho[1,2-b]furan which, when crystallized from chlorobenzene, melted at 2l0211 C. The measured wavelength of maximum excitation was 374 nm. and wavelength of maximum emission was 438 nm.

EXAMPLE 11 (a) A stirred mixture of 40.75 g. (0.25 mole) of 3,4- dichlorophenol, 42.12 g. (0.25 mole) of p-methylphenacyl chloride, 38.0 g. (0.275 mole) of potassium carbonate, 1.87 g. of potassium iodide and 500 ml. of acetone was refluxed with stirring for eight hours. The reaction mixture was allowed to cool and then poured into a large excess of cold water. A solid separated which was col lected and washed free of alkali with water. Following recrystallization from 2-ethoxyethanol, the thus obtained w-(3,4-dichlorophenoxy) p methylacetophenone melted at 118119 C.

(b) In a flask, 250 ml. of polyphosphoric acid was stirred and heated to 180 C. and to it there was added 36.9 g. (0.125 mole) of w-(3,4-dichlorophenoxy)-p-methylacetophenone from (a) above. The reaction mixture was stirred and held at a temperature between 180190 C. for eight hours. The progress of the reaction was followed by ultraviolet spectroscopy and the completion of the reaction was shown by the disappearance of the curve characteristics of the starting material and the appearance of a new maximum at 313 nm. The reaction mixture was allowed to cool and was poured into water. The solid that separated was collected on a filter, washed free of acid and recrystallized from Z-ethoxyethanol to obtain 5,6-dichloro 2 (p-tolyl)benzofuran, melting at 129- 130 C.

Following the procedure described in Example 1 above, equimolar quantities of the above-named 5,6- dichloro-Z-(p-tolyl)benzofuran and anil derivative of terephthalaldehydic acid were interacted in the presence of potassium tert-butoxide to give 5,6-dichl0ro-2-[4-(4- car-boxystyryl)phenylJbenzofuran, which, following sublimation, melted at 318322 C. The wavelength of maximum excitation of this compound was 367 nm., and

the wavelength of maximum emission was 421 nm.

EXAMPLE 12 (a) Following the procedure outlined in Example 11(a), 4-fluorophenol was interacted with an equimolar quantity of p-methylphenacyl chloride in the presence of potassium carbonate to give to (4 fluorophenoxy)-pmethylacetophenone which melted at 9596 C. after recrystallization from methanol.

(b) Following the procedure given in Example 11(b), the above-named w (4 fluorophenoxy)-p-methylacetophenone was heated with polyphosphoric acid to give fluoro-Z-(p-tolyl)benzofuran which, following recrystallization from 2-ethoxyethano1, melted at 156-157" C.

This compound showed the wavelength of maximum excitation at 313 nm. and the wavelength of maximum emission at 348 nm.

(c) The 5 fluoro-2 (p-tolyl)benzofuran from (b) above was condensed with an equimolar quantity of the anil derivative of terephthalaldehydic acid according to the method described in Example 1 above, to obtain 5- fluoro 2-[4-(4-carboxystyryl)phenyl]benzofuran. When purified by sublimation this product remained unmelted at 350 C. The wavelength of maximum excitation of this compound was 373 nm. and the wavelength of maximum emission was 422 nm.

EXAMPLE l3 Proceeding in a manner similar to that used in Example 1, 5-methyl-2-(p-tolyl)benzofuran. (2.22 g.; 0.01 mole) was interacted with 2.25 g. (0.01 mole) of the anil derivative of terephthalaldehydic acid in the presence of 6.72 g. (0.06 mole) of potassium tert-butoxide in ml. of dimethylformamide. The product thus produced was sublimed to obtain 5-methyl-2- [4-(4-carboxystyryl)- phenyl]benzofuran, melting at 355-358 C. The wavelength of maximum excitation of this compound was 374 nm. and the wavelength of maximum emission was 437 nm.

EXAMPLE 14 (a) A mixture of 24.2 g. (0.1 mole) of 5-chloro-2-(ptolyl)benzofuran and 32.20 g. (0.36 mole) of cuprous cyanide in 100 ml. of 1-rnethyl-2-pyrrolidone was refluxed for 26 hours. The reaction mixture was allowed to cool to 75 C. and the separated solid was collected by filtration. The product was washed with concentrated ammonia to remove the excess cuprous cyanide and the last traces of cuprous cyanide were removed by dissolving the ammonia washed compound in hot chlorobenzene and filtering. On cooling, 5-cyano-2-(p-tolyl)benzofuran separated from the chlorobenzene solution. After collection and drying in vacuo, the product melted at 191.5" C.

(b) Following the procedure given in Example 1, 5- cyano-2-(p-tolyl)benzofuran from above was reacted with an equimolar quantity of the anil derivative of terephthalaldehydic acid in the presence of potassium tert-butoxide using dimethylformamide as a solvent. Upon purification by sublimation, the thus obtained 5- cyano-2 [4-(4carboxystyryl)phenyllbenzofuran melted at 331333 C. The compound had the wavelength of maximum excitation at 366 nm. and the wavelength of maximum emission at 423 nm.

EXAMPLE 15 When an equivalent amount of 5-methoxy-3-anilinophthalide is substituted for the anil derivative of terephthalaldehydic acid in the procedure described in Example 1 above, there is obtained as the product 2-[4(2- carboxy-S-methoxystyryl) phenyl] benzothiophene.

EXAMPLE 16 When an equivalent amount of the anil derivative of 4-methyl-6-methoxyisophthalaldehydic acid is substituted for the anil derivative of terephthalaldehydic acid in the procedure described in Example 2 above, there is obtained as the product 2-[4-(6-methyl-4-methoxy-3-carboxystyryl)phenyl]benzofuran.

EXAMPLE 17 Following the procedure described in Example 3 above but using an equivalent amount of 6-bromo-3-anilinophthalide in place of the anil derivative of terephthalaldehydic acid, there is obtained as the product 5-phenyl- 2- [4- (2-carboxy-4-bromostyryl) phenyl 1 benzofuran.

EXAMPLE 18 When an equivalent amount of 6-methoxy-7-ethoxy-3- anilinophthalide is substituted for the anil derivative of 9 terephthalaldehydic acid in the procedure described in Example 12(c) above, there is obtained as the product fluoro-2-[4 (2-carboxy-3 ethoxy-4-methoxystyryl)- phenyl]benzofuran.

EXAMPLE 19 When an equivalent amount of the anil derivative of 5-chloro-3-anilinophthalide is substituted for the anil derivative'of terephthalaldehydic acid in the procedure described-in Example 4 above, there is obtained as the product 5 methoxy-Z [4-(2-carboxy-5 chlorostyryl)- phenyl]benzofuran.

EXAMPLE 20 Following the procedure described in Example 5 above but using an equivalent amount of the anil derivative of 3-methylterephthalaldehydic acid in place of the anil derivative of terephthalaldehydic acid, there is obtained as the product 5 chloro-2 [4 (2 methyl-4-carboxystyryl phenyl] benzofuran.

EXAMPLE 21 When an equivalent amount of 5,7-dimethoxy-3- anilinophthalide is substituted for the anil derivative of terephthalaldehydic acid in the procedure described in Example 13 above, there is obtained as the product 5- methyl-2 [4-(2carboxy-3,5 dimethoxystyryl)phenyl]- benzofuran.

EXAMPLE 22 Following the procedure described in Example 9 above but using an equivalent amount of the anil derivative of 3-bromoterephthalaldehydic acid in place of 3- anilinophthalide, there is obtained as the product 2-[4-(2- bromo-4-carboxystyryl)phenyl]naphtho[2,1-b]furan.

EXAMPLE 23 When an equivalent amount of 7 methyl-3-anilinophthalide is substituted for the anil derivative of tere- 'phthalaldehydic acid in the procedure described in Example 11(c) above, there is obtained as the product 5,6- -dich1oro 2- [4-(2-carboxy-3-methylstyryl)phenyl] benzofuran.

EXAMPLE 25 Following the procedure described in Example 14(b) above but using an equivalent amount of 5,7-dimethoxy-3- anilinophthalide in place of the anil derivative of terephthalaldehydic acid, there is obtained as the product 5- cyano 2-[4-(2-carboxy-3,S-dirnethoxystyryl)phenyl]benzofuran.

The dichlorobenzene and the trichlorobenzene used as recrystallization solvents in the Examples above are industrial grade solvents which are mixtures of various isomers. Thus, the dichlorobenzene is predominately ortho dichlorobenzene containing some of the two isomers, meta and para; and the trichlorobenzene is predominately 1,2,4- trichlorobenzene containing some of the other symmetrical and unsymmetrical trichlorobenzenes.

When the appropriate p-tolyl-substituted compound of Formula III or Formula IV and the anil derivative of the appropriate aldehyde are interacted in a manner similar to that described in Example 1, there are obtained:

5 n-Propyl-7-ethyl-2-[-methoxy-4-(3,4-dimethoxy-2-carboxystyryl)phenyl]benzofuran from the interaction of 5 n propyl-7-ethyl-2-(3-methoxy-4-tolyl)benzofuran and 6,7-dimethoxy-3-anilinophthalide;

4 Methoxy 7-bromo-2-[3-bromo-4-(3,5-dimethoxy-2- carboxystyryl)phenyl]benzothiophene from the inter- 10 action of 4-methoxy-7-bromo-2-(3-bromo-4-tolyl)benzothiophene and 5,7-dimethoxy-3-anilinophthalide;

5 Dimethylamino 2-[3-isopropyl-4-(2-bromo-4-carboxystyryl)phenyl]benzothiophene from the interaction of 5 dimethylamino 2-(3-isopropyl-4'tolyl)benzothiophene and the anil derivative of 3-bromoterephthaladehydric acid;

5 Flnoro 7-iodo 2-[3-iodo-4-(6-propoxy-2-carboxystyryl)phenyl]benzofuran from the interaction of 5- fiuoro 7-iodo-2-(3-iodo-4-tolyl)benzofuran and 4-propoxy-3-anilinophthalide;

7 n Hexyl-2-[3-iodo-4-(4-fiuoro-2-carboxystyryl)phenyl]benzofuran from the interaction of 7-n-hexyl-2-(3- iodo 4 tolyl)benzofuran and 6 fluoro 3-anilino phthalide;

2 [3 Bromo-4- (4-bromo-2-carboxystyryl)phenyl]naphtho[2,1-b]furan from the interaction of 2-(3-bromo- 4 tolyl)naphtho[2,l-b]furan and 6-bromo-3-anilinophthalide;

5 (4 Ethylphenyl)-2-[3-chloro-4-(3-methoxy-2-carboxystyryl)phenyl1benzothiophene from the interaction of 5 (4-ethylphenyl)-2-(3-chloro-4-tolyl)benzothiophene and 7-methoxy-3-anilinophthalide;

2 [3 n-Propyl-4-(2-iodo-4-carboxystyryl)phenyl]naphtho[2,1-b]furan from the interact on of 2-(3-n-propyl- 4-tolyl)naphtho[2,1-b]furan and 3-i0doterephthalaldehydic acid;

5,7 Di n-hexyl-Z-[3-n-pentyl-4-(2-methyl-4-carboxystyryl)phenyl]benzothiophene from the interaction of 5,7- di-n-hexyl-2-(3-n-pentyl-4-tolyl) benzothiophene and the anil derivative of 3-methylterephthalaldenhydic acid;

6 (4 Chlorophenyl)-2-[3-bromo-4-(3-methyl-2-carboxystyryl)phenyl]benzofuran from the interaction of 6- (4 chlorophenyl)-2-(3-bromo-4-tolyl)benzofuran and 7-methyl-3-anilinophthalide;

2 [3 n-Propyl-4-(4-propoxy-6-methyl-3-carboxystyryl) phenyl]naphtho[1,2 b]furan from the interaction of 2- (3-n-propyl-4-tolyl)naphtho[1,2-b]furan and the anil derivative of 4 methyl 6-propoxyisophthalaldehydic acid;

2 [3-Bromo-4-(3-n-butyl-2-carboxystyryl)phenyl]naphtho[2,1-b]furan from the interaction of 2-(3-bromo-4- tolyl)naphtho[2,1b]furan and 7 n =butyl-3-anilinophthalide;

5 Acetamido 2-[3-n-butyl-4-(5-chloro-2-carboxystyryl) phenyl]benzothiophene from the interaction of S-acetamido-2-(3-n-buty1-4-tolyl)benzothiophene and S-chloro-3-anilinophthalide;

5 Ethoxy 2-[3-n-pentyl-4- (4-iodo-2-carboxystyryl)phenyl]benzothiophene from the interaction of 5-ethoxy-2- (3 n-pentyl-4-tolyl)benzothiophene and 6-iodo-3-anilinophthalide;

6 Methoxy 7-isopropoxy-2-[3-n-propyl-4-(3,5-dimethoxy-2-carboxystyryl)phenyl]benzofuran from the interaction of 6 methoxy 7-isopropoxy-2-(3-n-propyl-4- tolyl)benzofuran and 5,7-dimethoxy-3-anilinophthalide;

2 [3 n-Pr0py1-4-(S-methoxy-Z-car boxystyryl)phenyl] naphtho[2,l-b]furan from the interaction of 2-(3-npropyl 4-tolyl)naphtho[2,1-b]furan and 5-methoxy-3- anilinophthalide;

2 [3 n-Propyl-4-(4-iodo-2-carboxystyryl)phenyl]naphtho[l,2-b]furan from the interaction of 2-(3-n-propyl- 4 tolyl)naphtho[1,2-b]furan and 6 iodo 3-anilinophthalide;

5 (1 Methylpropyl)-2-[3-fluoro-4-(2-n-butyl-4-carboxystyry1)phenyl]benzofuran from the interaction of 5- (1 methylpropyl)-2-(3-fiuoro-4-tolyl)benzofnran and the anil derivative of 3 n butylterephthalaldehydic acid; and l 4 2 [3 Iod0-4-(2-bromo-4-carboxystyryl)phenyl]naphtho[2,3-b]furan from the interaction of 2-(3-iodo-4- tolyl)naphtho [2,3-b)furan and the anil derivative of 3- bromoterephthalaldehydic acid.

1 l Esterification of the appropriate carboxylic acid-substituted compound of Formula I with the appropriate lower alkanol or lower alkanediol according to the procedures described either in Example 6 or Example 7 hereinabove, yields the following compounds:

-F1uoro-7-iodo-2-[3-iodo-4-(p propoxy-Z-carboethoxystyryl)phenyl]benzofuran from the interaction of the acid chloride of 5-fluoro-7-iodo-2-[3-iodo 4 (6-propoxy 2 carboxystyryl)phenyl]benzofuran with ethyl alcohol;

5,7-Di-n-hexyl-2-[3-n-pentyl-4-(2-methyl 4 carbopropoxystyryl)phenyl]benzothiophene from the interaction of the acid chloride of 5,7-di-n-hexyl 2 [3 npentyl-4-(2-methyl 4 carboxystyryl)phenyl]benzothiophene with fi-propyl alcohol;

2-[3-n-Propyl 4 (4-iodo 2 carboisopropoxystyryl) phenyl]naphtho[1,2-b1furan from the interaction of the acid chloride of 2-[3-n-propyl-4-(4-iodo-2-carboxystyryl)phenyl] naphtho[ 1,2-b]furan with isopropyl alcohol;

2-{3-n-Propyl-4-[2-iodo 4 carbo(3-hydroxypropoxy) styryl]phenyl}naphtho[2,1-b1furan from the interaction of the acid chloride of 2-[3-n-propyl-4-(2-iodo-4- carboxystyryl)pl1enyl]naphtho[2,1 b]furan with 1,3- dihydroxypropane; and

2-{3-Iodo-4-[2-bromo 4 carbo(2 hydroxypropoxy) styryl]phenyl}naphtho[2,3-b]furan from the interaction of the acid chloride of 2-[3-iodo-4-(2-bromo-4- carboxystyryl)phenyl]naphtho[2,3 b]furan with 1,2 dihydroxypropane.

The elfectiveness of the optical brightening agents prepared above is determined by a variety of tests. The tests include dyeings made on various fabrics. Such dyeings can be accomplished by subjecting cloth samples to repeated launderings from detergent solutions containing optical brightening quantities of the compounds. Another' method previously described hereinabove is to impregnate textile fibers from an aqueous dispersion followed by heat treating of the impregnated fibers. Still another method involves the incorporation of the compound to be tested into a polymeric melt. In each of these tests, the substrate treated with the optical brightening agent is subjected to color comparison with untreated samples of the same substrate. A color difference meter is used to measure differences in shade of whiteness between the samples. The following procedure, which is illustrative of one of these methods for determining the elfectiveness of the optical brightening agents of this invention, describes the test method and the results obtained for the compound of Example 5, a particularly preferred compound for incorporation into normally solid, fiber and filmforming polymeric materials, when incorporated into polyethylene terephthalate melts.

A solution of 5-chloro-2-[4-(4-carboxystyryl)phenyl] benzofuran (Example 5) in dimethyl terephthalate was prepared by intermixing 0.04 g. of the brightener with 10.00 g. of dimethyl terephthalate and then melting the two solids together, with continual stirring and under a carbon dioxide atmosphere, by immersing the container in a bath of diethyl phthalate which was then heated to 200 C. during a period of about 15-20 minutes. The fluid mixture was then poured into a mortar and ground to a fine powder. The solid solution of brightener in dimethyl terephthalate was incorporated into polyethylene terephthalate by blending 1.5 g. of the brightener-dimethyl terephthalate powder with 18.0 g. of predried polyethylene terephthalate chips and 0.5 g. of dimethyl terephthalate. The mixture was melted under a carbon dioxide atmosphere by immersing the container in a bath of diethyl phthalate at 115 C. after which the bath was heated to boiling (295-7" C.). The melt was stirred for five minutes, and it then was removed from the bath and allowed to cool to room temperature, continually under 1 2 carbon dioxide. The polyethylene terephthalate casting was then broken up and ball milled with stoneware pellets in distilled water. The particles were dried and screened, and those passing through a 40 mesh screen were packed into a 5 cm. polystyrene Petri dish. The color of the sample was then measured on a color difference meter (Hunterlab Model D-25, Hunter Associates Laboratory, McLean, Va.) in comparison with a standard magnesium oxide plate. These values were then compared with those for a blank sample preparedin the identical way except that the optical brightener was omitted. The values of the blank sample were determined at the same time as those of the sample tested. Following are the readings obtained in comparison with the standard magnesium oxide plate:

Hunterlab D-25 readings L a Y (1 Blank polyethylene terephthalate (PET) 96. 2 +0. 5 +2. 6 PET containing 0.03 percent 5-ehloro-2-[4-(4- cnrboxystyryl) phenyHbenZofuran 96. 6 +3. 2 3. 4

wherein Q is a monovalent aromatic heterocyclic radical selected from the class having the formulas X is oxygen or sulfur; Z is naphtho; R is hydrogen, lower alkyl having one to three carbon atoms or hydroxy-lower alkyl having two or three carbon atoms; R and R are the same or different and are members of the class consisting of hydrogen, alkyl having one to six carbon atoms, alkoxy having one to six carbon atoms, and halo; R and R are the same or different and are members of the class consisting of hydrogen, alkyl having one to six carbon atoms, alkoxy having one to six carbon atoms, cyano, halo, dialkylamino wherein each alkyl has one to six carbon atoms, alkanoylamino having one to six carbon atoms, phenyl, phenyl substituted by alkyl having one to six carbon atoms, halo, alkoxy having one to six carbon atoms, and alkanoylamino having one to six carbon atoms.

2. A normally solid, fiber and film-forming polyester or nylon polymeric material according to Claim 1 having incorporated therein approximately 0.005 to 0.5 percent by weight of said polymeric material of a fluorescent compound of the formula in which R, R R R and R each have the same meanings indicated in Claim 1.

3. A normally solid, fiber and film-forming polyester ornylon polymeric material according to Claim 2 having incorporated therein approximately 0.005 to 0.5 percent by 13 14 weight of said polymeric material of 5-ch1or0-2-[4-(4- OTHER REFERENCES carboxystyryDphenyl]benzofuran.

4. A normally solid, fiber and film-forming polyester g gg g :gg g zs gg i g i g ia gg material according to Claim 3 selected from the class consi i t etaljz Helv. Chimica Acta, vol. 52 (196 9) pp.

sisting of poly(ethylene terephthalate) and poly(l,4-

cyclohexylenedimethylene terephthalate) having incorpo- 5 1282 1296 1305' rated therein approximately 0.005 to 0.5 percent by DANIEL E WYMAN Primary Examiner weight of the fluorescent compound, 5-chloro-2-[4-(4-carboxystyrynphenyl]benzofumm A. P. DEMERS, Assistant Examiner References Cited 10 US. Cl. X.R. UNITED STATES PATENTS 117-335 R; 2 0-47 NP, 37 P, 40 P, 3,697,513 10/1972 Siegrist 117-335 R CA 3,682,900 8/1972 Liechti et al. 2s2 301.2 W

3,674,781 7/1972 Schinzel et a1. 252 301.2 W 15 

